This invention relates to a plural power path torque transfer mechanism and more particularly to a clutching arrangement for establishing the power paths.
It is well recognized in the art that the tractive efforts of a vehicle are substantially improved if driving torque is applied to both front and rear axles. This concept has long been used in military and off-highway vehicles designed to operate over unimproved terrain by providing a mechanism to transfer torque between the axles. Ordinarily the torque transfer mechanism is connected to a transmission which is driven in the conventional manner by a prime mover, and is adapted to split the torque between the front and rear axles.
In recent years much effort has been devoted to part-time torque transfer mechanisms, i.e., those having a plurality of power paths selectively engageable by a vehicle operator. Common part-time torque transfer mechanisms are designed with all constant mesh gearing and a pair of shiftable clutch collars for selecting the desired power path. In these devices it is advantageous to interconnect the clutch collars so that a single operating means may effect shifting of both collars to establish the power path selection.
However, certain problems may arise in connection with this type system. One problem is that the clutches provided on the various gears for cooperating with the clutch collars require excessive movement of the collars to complete the different shifting operations. This not only adds to the length of the unit but is also undesirable from a control standpoint because it required additional space to achieve the clutching operation.